AN EFFICIENT NONENUMERATIVE METHOD TO ESTIMATE THE PATH DELAY-FAULT COVERAGE IN COMBINATIONAL-CIRCUITS

A method to estimate the coverage of path delay faults of a given test set, without enumerating paths, is proposed. The method is polynomial in the number of lines in the circuit, and thus allows circuits with large numbers of paths to be considered under the path delay fault mod el. Several levels of approximation, with increasing accuracy and incr easing polynomial complexity, are proposed. Experimental results are p resented to show the effectiveness and accuracy of the estimate in eva luating the path delay fault coverage. Combining this non enumerative estimation method with a test generation method for path delay faults would yield a cost effective method to consider path delay faults in l arge circuits, which are beyond the capabilities of existing test gene ration and fault simulation procedures, that are based on enumeration of paths.